1/*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright © 2022 Keith Packard
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above
14 *    copyright notice, this list of conditions and the following
15 *    disclaimer in the documentation and/or other materials provided
16 *    with the distribution.
17 *
18 * 3. Neither the name of the copyright holder nor the names of its
19 *    contributors may be used to endorse or promote products derived
20 *    from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
27 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
33 * OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35#include <picolibc.h>
36
37#define PPC_BIT(bit)            (0x8000000000000000ULL >> (bit))
38	.text
39	.section	.text.init.enter
40	.global _start
41	.type	_start, @function
42_start:
43	/* Get stack pointer */
44	lis	%r1,__stack@h
45	ori	%r1,%r1,__stack@l
46
47#ifdef __PPC64__
48#define TARGET_THREAD_SSP_OFFSET	0x7010
49#else
50#define TARGET_THREAD_SSP_OFFSET	0x7008
51#endif
52	/* Compute stack protector location */
53	lis	%r13,(__stack_chk_guard+TARGET_THREAD_SSP_OFFSET)@h
54	ori	%r13,%r13,(__stack_chk_guard+TARGET_THREAD_SSP_OFFSET)@l
55
56#ifdef __PPC64__
57	/* Where are we? */
58	bl	here
59here:	mflr	%r2
60
61	/* Figure out the initial TOC value */
62	ld	%r2,(toc-here)(%r2)
63#endif
64
65	mfmsr	%r0
66	/* Enable FPU */
67	ori	%r0,%r0,PPC_BIT(50)
68	/* Enable VSX */
69	oris	%r0,%r0,PPC_BIT(40)>>16
70	/* Enable Altivec */
71	oris	%r0,%r0,PPC_BIT(38)>>16
72	mtmsr	%r0
73
74	/*
75	 *   r8 is the OPAL base
76	 *   r9 is the OPAL entry point point
77	 */
78	mr	%r3, %r8
79	mr	%r4, %r9
80	bl	_cstart
81#ifdef __PPC64__
82	.align	3
83toc:
84	.quad 	.TOC.@tocbase
85#endif
86
87